          (>= ?vcf 25))))
 
 (defn static-src [{:keys [vcf-limit]} pail-path]
+  ;; screen out border pixels later - doing it here will remove non-
+  ;; but nearly water pixels before they can be included as neighbors
   (let [[vcf hansen ecoid gadm border]
         (map (comp static-tap (partial split-chunk-tap pail-path))
              [["vcf"] ["hansen"] ["ecoid"] ["gadm"] ["border"]])]

              vcf-step
              ([:tmp-dirs vcf-path]
                 (?- (hfs-seqfile vcf-path)
                     (<- [?subpail ?chunk]
                         ((constrained-tap pail-path "vcf" s-res "00") ?subpail ?chunk))))

              ndvi-step
              ([:tmp-dirs ndvi-path]
                 (?- (hfs-seqfile ndvi-path)

  [chunk-src]
  (<- [?s-res ?mod-h ?mod-v ?sample ?line ?val]
      (chunk-src _ ?chunk)
      (thrift/unpack ?chunk :> _ ?loc ?data _ _)
      (thrift/get-field-value ?data :> ?val)
      (thrift/unpack ?loc :> ?s-res ?mod-h ?mod-v ?sample ?line)))

(defn country-tap
  [gadm-src convert-src]
